Abstract
BackgroundUltramarathon runners commonly believe that sodium replacement is important for prevention of muscle cramping, dehydration, hyponatremia, and nausea during prolonged continuous exercise. The purpose of this study was to measure total sodium intake to determine if these beliefs are supported.MethodsParticipants of a 161-km ultramarathon (air temperature reaching 39 °C) provided full dietary information during the race, underwent body weight measurements before and after the race, completed a post-race questionnaire about muscle cramping and nausea or vomiting during the race, and had post-race plasma sodium concentration measured.ResultsAmong 20 finishers providing dietary data, mean (±SD) total sodium intake was 13,651 ± 8444 mg (range 2541–38,338 mg), and sodium in food and drink accounted for 66 % of the sodium when averaged across subjects (range 34–100 %). Sodium intake rates were similar when comparing the 10 % of subjects who were hyponatremic with those who were not hyponatremic, the 39 % with muscle cramping or near cramping with those without cramping, and the 57 % who reported having symptoms of nausea or vomiting with those without these symptoms. Weight change between race start and finish was significantly related to rate of sodium intake (r = 0.49, p = 0.030) and total sodium intake (r = 0.53, p = 0.016), but the maximum weight loss among those taking the least total sodium (<4400 mg total sodium during the race) was 4–5 % below the weight measured immediately pre-race.ConclusionsExercise-associated muscle cramping, dehydration, hyponatremia, and nausea or vomiting during exercise up to 30 h in hot environments are unrelated to total sodium intake, despite a common belief among ultramarathon runners that sodium is important for the prevention of these problems.
Highlights
Ultramarathon runners commonly believe that sodium replacement is important for prevention of muscle cramping, dehydration, hyponatremia, and nausea during prolonged continuous exercise
At the 2014 WSER, we extended these findings to demonstrate that supplemental sodium enhanced body weight maintenance, but those who were not using sodium supplements maintained a more appropriate hydration level than those consistently using sodium supplements [11]
We found that the use of sodium supplements and intake rate of sodium in supplements did not differ between those with and without muscle cramping [12] and that inadequate sodium supplementation was not a cause for the development of hyponatremia [1]
Summary
Ultramarathon runners commonly believe that sodium replacement is important for prevention of muscle cramping, dehydration, hyponatremia, and nausea during prolonged continuous exercise. Ultramarathon runners have a common belief that sodium intake during exercise prevents muscle cramping, dehydration, and hyponatremia [1]. There is a conventional perception that fluid or electrolyte imbalances are a cause of nausea, a common symptom during ultramarathons [2,3,4,5,6,7], and that sodium intake may prevent such symptoms [8]. For these reasons, most ultramarathon runners use sodium supplements during competitions. The rate of sodium intake in supplements and in buffered sodium supplements was found to be unrelated to symptoms of nausea or vomiting [13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
